Optimized Liquid-Phase Oxidation

Abstract

Disclosed is an optimized process and apparatus for more efficiently and economically carrying out the liquid-phase oxidation of an oxidizable compound. Such liquid-phase oxidation is carried out in a bubble column reactor that provides for a highly efficient reaction at relatively low temperatures. When the oxidized compound is para-xylene and the product from the oxidation reaction is crude terephthalic acid (CTA), such CTA product can be purified and separated by more economical techniques than could be employed if the CTA were formed by a conventional high-temperature oxidation process.

1 . In a bubble column reactor for reacting a predominately liquid-phase stream and a predominately gas-phase stream, the improvement comprising:
 a vessel shell including a reaction section and a disengagement section,   wherein said reaction section defines an elongated reaction zone having a maximum diameter (D) and a maximum length (L) of at least about 30 meters, wherein said reaction zone presents normally-upper and normally-lower ends spaced from one another by said length (L),   wherein said disengagement section is located above said reaction section and defines a disengagement zone in fluid communication with said reaction zone, wherein said disengagement zone has a maximum diameter (X) and a maximum height (Y), and   wherein said vessel shell has an X:D ratio of at least about 1.1:1.   
     
     
         2 . The bubble column reactor of  claim 1  wherein said reaction zone has an L:D ratio of at least about 6:1. 
     
     
         3 . The bubble column reactor of  claim 1  wherein said bubble column reactor has an L:Y ratio in the range of from about 2:1 to about 24:1. 
     
     
         4 . The bubble column reactor of  claim 1  wherein said reaction zone has a total volume of at least about 250 cubic meters. 
     
     
         5 . The bubble column reactor of  claim 1  wherein said reaction zone has an L:D ratio in the range of from about 8:1 to about 20:1, wherein said bubble column reactor has an L:Y ratio in the range of from about 3:1 to about 20:1, wherein said reaction zone has a total volume of at least about 500 cubic meters. 
     
     
         6 . The bubble column reactor of  claim 1  wherein said reaction zone has a total volume of at least about 1,000 cubic meters. 
     
     
         7 . The bubble column reactor of  claim 1  wherein said bubble column reactor further comprises a reflux distributor disposed in said disengagement section and operable to discharge a liquid reflux stream toward said reaction zone. 
     
     
         8 . The bubble column reactor of  claim 7  wherein said reflux distributor is configured to discharge said liquid reflux stream in a manner such that the discharged liquid reflux stream affects at least about 75 percent of the maximum horizontal cross-sectional area of said disengagement zone. 
     
     
         9 . The bubble column reactor of  claim 1  wherein said reactor further comprises one or more gas openings for introducing said gas-phase stream into said reaction zone, wherein a majority of the cumulative open area defined by all of said gas openings is located within about 0.25D of said normally-lower end of said reaction zone. 
     
     
         10 . The bubble column reactor of  claim 9  wherein substantially all of the cumulative open area defined by all of said gas openings is located within about 0.022L and about 0.25D of said normally-lower end of said reaction zone. 
     
     
         11 . The bubble column reactor of  claim 9  wherein said reactor further comprises one or more liquid openings for introducing said liquid-phase stream into said reaction zone, wherein at least about 30 percent of the cumulative open area defined by all of said liquid openings is located within about 1.5D of the gas opening located closest to said normally-lower end. 
     
     
         12 . The bubble column reactor of  claim 9  wherein said reactor further comprises one or more liquid openings for introducing said liquid-phase stream into said reaction zone, wherein at least two of said liquid openings are spaced from one another by at least about 0.5D.